1. Field of the Invention
The subject disclosure relates to surgical instruments and methods for cutting and applying surgical staples to body tissue, and more particularly, to a surgical instrument for progressively forming an incision in body tissue while placing staples on each side of the incision.
2. Background of the Related Art
Many surgical procedures often require the application of one or more surgical fasteners to body organs and tissue. In many instances, the fasteners used are unitary metal staples. Such metal staples are used in numerous types of surgical procedures. In most surgical procedures, the staples are applied directly to the body tissue requiring attachment, reattachment, ligation, etc. In certain other procedures, staples are used to attach an intermediate object to the body tissue. In still other procedures, cutting of the body tissue in areas adjacent the stapling is also desired.
In view of the above, surgical stapling instruments are known wherein tissue is first grasped or clamped between opposing jaw structure and then fastened by means of fasteners. In some instruments, a knife is provided to cut tissue which has been joined by the fasteners. Instruments for this purpose can include two elongated jaws which are respectively used to capture or clamp tissue. Typically, one of the jaws carries a disposable cartridge wherein a plurality of staples are arranged in a row while the other jaw has an anvil for forming the staple legs as the staples are driven from the cartridge. Generally, the stapling operation is effected by a camming element which travels longitudinally through the cartridge and acts upon individual staple pushers to sequentially eject the staples from the cartridge. A knife can be positioned in such a manner so as to operate sequentially immediately behind the camming element and laterally positioned between the staple rows to longitudinally cut and/or open the stapled tissue. Such instruments are disclosed, for example, U.S. Pat. No. 3,490,675 to Green and U.S. Pat. No. 5,901,895 to Green.
An instrument disclosed in U.S. Pat. No. 3,499,591 to Green applies a double row of staples on each side of the incision. This is accomplished by a cartridge assembly wherein a cam member moves within an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are positioned in such a manner so as to be contacted by the longitudinally moving cam to effect ejection of the staples. The cartridge assemblies typically come in a plurality of sizes, each varying in both length and number of staples contained therein. Depending on the procedure to be performed, the surgeon must select the appropriate cartridge assembly.
The instruments described above were all designed for use in surgical procedures wherein surgeons have direct access to the operation site. However, in endoscopic or laparoscopic procedures, surgery is performed through a small incision or through narrow cannulae inserted through entrance wounds in the skin. In order to address the specific needs of endoscopic and/or laparoscopic surgical procedures, endoscopic surgical stapling devices such as those disclosed in U.S. Pat. No. 5,040,715 and U.S. Pat. No. 5,318,221, both to Green et al., have been developed. In general, these instruments are provided with clamping structure to effect approximation of an anvil and a staple cartridge to secure tissue therebetween, and staple firing structure to effect sequential ejection of a plurality of staples from the staple cartridge after the tissue has been secured.
It is the case with most prior art stapling instruments designed to sequentially place one or more lines of staples on both sides of an incision, that once the staple firing process begins, the surgeon must typically complete the entire stapling stroke. Otherwise, if the surgeon stops stapling mid-stroke, some of the staples will be only partially formed due to the terminated movement of the advancing camming member relative to the leading staple pushers. This can complicate the surgical procedure.
While prior art stapling and cutting instruments have proven useful, it would be beneficial to provide a surgeon with an instrument that provides greater control over staple placement along an incision during an endoscopic surgical procedure so as to alleviate the problems associated with a sequentially fired stapling instrument.